A locking device of the kind mentioned above is known from document DE 10 2010 044 702 A1 and serves for fixing a rigid roof element, which can be a front bow of a folding top or a rigid roof segment of a retractable hard top (RHT), to the front cowl of the vehicle in question. The locking device comprises a locking support, which serves as a casing and which can be connected to the rigid roof element. A locking hook is pivotable around a bearing journal movable in the locking support. The locking hook has a hook section that can be displaced between a lowered release position and a raised locked position, in which the hook section is engaged with a corresponding locking element formed at the front cowl. For displacing the locking hook, the locking device has a driving mechanism, by means of which the bearing journal can be moved in such a manner that a displacing movement is introduced into the locking hook. Via a link arrangement of the driving mechanism, the driving torque generated by a driving motor is transmitted to a crosshead, on which the bearing journal of the locking hook is mounted and which is movable in corresponding guiding tracks of the locking support. In this locking device, the position of the locking hook with respect to the locking support is not always unambiguously defined. In fact, the locking hook is movable in the transverse direction because it can be turned about a crosshead axis that extends in the vertical direction. Additionally, a magnet is used to retain the locking hook, said magnet pulling the locking hook against a sliding surface. Also, the driving mechanism has an elaborate design because the crosshead is connected to a driving link arrangement both at the top and at the bottom. This is disadvantageous in terms of height and weight and is also reflected in the production costs of the locking device. Furthermore, merely a pulling force extending between the bearing journal and the hook section can be generated in this locking device. A force component perpendicular to said direction cannot be generated.